Well bore data - transmission apparatus with debris clearing apparatus

ABSTRACT

In the representative embodiment of the apparatus of the present invention disclosed herein, a first ported or grooved cylindrical member is coaxially mounted within a drill string for directing drilling fluids flowing through the apparatus along one or more selected flow paths toward a second ported or grooved cylindrical member which is coaxially mounted in the drill string adjacent to the first member for rotation in a transverse plane cutting the flow paths to cyclically obstruct these flow paths. An electric motor is cooperatively coupled by a shaft to the rotatable member for driving the first member at a selected speed for developing an acoustic signal of a desired frequency as the flow paths are momentarily obstructed at periodic intervals. To prevent jamming of the rotating member which would otherwise occur should debris carried in the circulating drilling fluid become lodged between the two signal-producing members, the rotating member is cooperatively mounted on the motor shaft to move away from the fixed member either in response to a significant increase of the pressure differential across the two members or in response to a significant increase in rotative torque as might occur by an accumulation of debris or the like between the two members tending to at least slow the rotating member. Biasing means are further provided to maintain the rotating member in its normal position as well as to restore the rotating member to its normal operating position adjacent to the second member once the debris has been cleared from between the signal-producing members by the continued flow of the drilling fluid.

United States Patent [191 Cubberly, Jr.

[ 1 Oct. 9, 1973 WELL BORE DATA TRANSMISSION APPARATUS WITH DEBRIS CLEARING APPARATUS [75] Inventor: Walter E. Cubberly, Jr., Houston,

Tex.

[73] Assignee: Schlumberger Technology Corporation, New York, NY.

[22] Filed: June 15, 1972 [21] Appl. No.: 263,023

Primary Examiner-Benjamin A. Borchelt Assistant Examiner-H. A. Birmiel Attorney-Ernest R. Archambeau, Jr. et al.

[57] ABSTRACT ln the representative embodiment of the apparatus of the present invention disclosed herein, a first ported or grooved cylindrical member is coaxially mounted within a drill string for directing drilling fluids flowing through the apparatus along one or more selected flow paths toward a second ported or grooved cylindrical member which is coaxially mounted in the drill string adjacent to the first member for rotation in a transverse plane cutting the flow paths to cyclically obstruct these flow paths. An electric motor is cooperatively coupled by a shaft to the rotatable member for driving the first member at a selected speed for developing an acoustic signal of a desired frequency as the flow paths are momentarily obstructed at periodic in tervals. To prevent jamming of the rotating member which would otherwise occur should debris carried in the circulating drilling fluid become lodged between the two signal-producing members, the rotating member is cooperatively mounted on the motor shaft to move away from the fixed member either in response to a significant increase of the pressure differential across the two members or in response to a significant increase in rotative torque as might occur by an accumulation of debris or the like between the two members tending to at least slow the rotating member. Biasing means are further provided to maintain the rotating member in its normal position as well as to restore the rotating member to its normal operating position adjacent to the second member once the debris has been cleared from between the signal-producing members by the continued flow of the drilling fluid.

25 Claims, 5 Drawing Figures PAIENIED 91913 3.764.969

sum 2 0r 2 MOTOR DRIVERS SQUARE 4 WAVE 1 SUPPLY i I i 2 1 l 57 1 55 52 I REFERENCE l g A- i 60 COMPARATOR COUNTER 59 TACH. RECT.

FIGS

WELL BORE DATA TRANSMISSION APPARATUS WllTIll DEBRIS CLEARING APPARATUS Various downhole signaling devices have been proposed heretofore for transmitting data representative of one or more downhole conditions to the surface during the drilling of a borehole. One of the morepromising devices of this nature is a fluid-dynamic transducer or a so-called siren (such as shown generally at 62 in U.S. Pat. No. 3,309,656) that is selectively arranged for developing acoustic signals which are transmitted to the surface through the circulating mud stream in the drill string. A typical one of these sirens includes a grooved or ported rotor which is rotatively driven at one or more selected speeds across one or more jets of drilling mud issuing from a fixed grooved or ported stator for producing acoustic signals at frequencies related to the design of the siren members, the properties of the drilling mud, and the rotational speed of the rotor. Thus, by selectively controlling the rotational speed of the rotor in accordance with variations in a measured downhole condition, the siren can be selectively operated as required for transmitting coded acoustic signals to the surface which are representative of the measurements of the downhole condition.

Although sirens such as these have other advantages, one of the paramount advantages in using these signaling devices is that acoustic signals can be efficiently produced thereby within a frequency span of about to 300-cycles/second. As noted in the aforementioned patent, frequencies above this range are subject to significant attenuation; and it is, therefore, preferred to operate these sirens to produce signals at frequencies between about 10 to 60-cycles/second. Although signaling devices such as these have shown significant promise for commercial applications, the narrow spacing between the two siren members required to produce satisfactory acoustic signals makes these sirens particularly susceptible to being jammed or easily obstructed either by drilling mud solids or by well debris and the like which is prevalent in the circulating mud stream in a typical borehole.

Accordingly, it is an object of the present invention to provide a new and improved well bore datatransmission system for producing selectively coded acoustic signals in a selected frequency range in debrisbearing well bore fluids such as a circulating stream of drilling mud.

This and other objects of the present invention are attained by providing a well tool adapted to be connected in a pipe string such as a drill string having a drill bit dependently coupled thereto and arranged for excavating a borehold as a drilling fluid is circulated through a fluid passage in the tool and the drill string. To generate distinctive acoustic signals in the circulating fluid representative of one or more downhole measurements, acoustic signaling means on the tool include a selectively controlled electric motor rotatively driving a flow-controlling member arranged to the positioned immediately adjacent to another flowcontrolling member within the fluid passage so as to cyclically vary the degree of flow obstruction presented by the two flow-controlling members in cooperation with one another for producing an acoustic signal. The acoustic signaling means further include control means responsive to slowing of the motor by solid materials or debris between the flow-controlling members tending to either increase the pressure differential across the flow-controlling members or increase the torque required to drive the rotating member for temporarily separating the members so as to allow debris and the like to be carried free of the two members by the flowing mud stream. The control means are further responsive to either a decrease in the pressure differential to its usual operating range or a decrease in the driving torque for restoring the flow-controlling members to their signal-producing positions once debris has been freed from between the two members. Means are further provided for selectively reversing the rotational direction of'the rotating member as a further aid in clearing debris and other solid materials from the acoustic signaling means.

The novel features of the present invention are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may be best understood by way of the following description of exemplary apparatus employing the principles of the invention as illustrated in the accompanying drawings, in which:

FIG. 1 shows a new and improved well tool arranged in accordance with the present invention as it will appear while coupled in a drill string during the course of a typical drilling operation;

FIG. 2 depicts a preferred embodiment of the acoustic signaler employed with the well tool shown in FIG.

FIGS. 3 and 4 are cross-sectional views respectively taken along the lines 3-3 and 4-4 in FIG. 2; and

FIG. 5 schematically illustrates a representative control circuit which may be employed in the present invention.

Turning now to FIG. 1, a new and improved well tool 10 arranged in accordance with the present invention is depicted coupled in a typical drill string 11 having a rotary drill bit 12 dependently coupled thereto and adapted for excavating a borehole 13 through various earth formations as at 14. As the drill string 11 is rotated by a typical drilling rig (not shown) at the surface, substantial volumes of the drilling fluid or so-called mud" are continuously pumped downwardly through the tubular drill string and discharged from the drill bit 12 to cool the bit as well as to carry earth borings removed by the bit to the surface as the mud is returned upwardly along the borehold 13 exterior of the drill string. As is typical, the mud stream is circulated by employing one or more high-pressure mud pumps (not shown) which continuously draw the fluid from a storage pit or surface vessel (not shown) for subsequent recirculation by the mud pumps. It will be appreciated, therefore, that the circulating mud stream flowing through the drill string 11 serves as a transmission medium that is well suited for transmitting acoustic signals to the surface at the speed of sound in the particular drilling fluid.

In accordance with the principles of the present invention, data-transmitting means 15 are arranged on the well tool 10 and include one or more conditionresponsive devices, as at 16 and 17, respectively coupled to an appropriate measurement encoder l8 operatively arranged to produce a series of electrical coded data signals that are representative of the measurements being obtained by the condition-responsive devices. Although a self-contained battery power supply could be employed, as shown at 19 it is preferred to employ a reaction-type turbine driving a generator for utilizing the circulating mud stream as a motivating source to generate electric power for operation of the new and improved data-transmitting means 15. As will subsequently be explained in greater detail, the datatransmitting means further include acoustic signaling meand 20 including an electric motor 21 coupled to the encoder l8 and operatively arranged to respond to its coded output signals for rotatively driving an acoustic signaler 22 by way of a typical gear train 23 to successively interrupt or obstruct the flow of the drilling fluid through the drill string lll. The resulting acoustic signals produced by the acoustic signaler 22 will be transmitted to the surface through the mud stream flowing within the drill string 11 as encoded representations or data signals indicative of the one or more downhole conditions respectively sensed by the condition-measuring devices 16 and 17. As these data signals are successively transmitted to the surface, they are detected and converted into meaningful indications or records by suitable acoustic signal detecting-andrecording apparatus 24 such as that disclosed in either U.S. Pat. No. 3,309,656, US. Pat. No. 3,488,629, or US. Pat. No. 3,555,504.

Turning now to FIG. 2, a cross-sectioned elevational view is shown of a preferred embodiment of the new and improved acoustic signaler 22. As seen there, the tool 10 includes a tubular body 25 which is cooperatively arranged in a typical manner with appropriate end connections (not shown) to allow the body to be tandemly coupled in the drill string 11. The tubular body 25 includes an axial fluid passage 26 for conducting the drilling fluid flowing through the drill string 11 to the drill bit 12 therebelow. As illustrated in FIGS. 2 and 3,the new and improved acoustic signaler 22 includes an annular ported or internally grooved flowdirecting member 27 which is coaxially arranged within the flow passage 26 and secured to the body 25 as by a set of complementary threads 28. As will subsequently be explained in greater detail, in the preferred embodiment of the acoustic signaling means 20 the flow-directing member 27 is provided with a plurality of flow passages defined by inwardly opening longitudinal grooves, as at 29, having a substantially rectangular or square cross-sectional configuration which are respectively cut at equal circumferentially spaced intervals around the interior wall of the flow-directing member parallel to and at a uniform radius from the longitudinal or central axis 30 of the tool body 25. To minimize turbulence and other disturbances to the flow of the downwardly flowing drilling fluid through the tool 10, the upper face of the flow-directing member 27 is concavely shaped as at 31.

As best seen in FIGS. 2 and 4, in its preferred embodiment the acoustic signaler 22 further includes a rotatable ported or externally grooved flow-obstructing member 32 which is cooperatively arranged on the upper end of the output shaft 33 of the gear train 23 and coaxially disposed within the central fluid passage 26 for rotation in a transverse plane of rotation normally lying immediately below the flow-directing member 27. As illustrated in FIG. 2, the opposed lower and upper faces 34 and 35 of the flow-directing member 27 and the rotating flow-obstructing member 32, respectively, are preferably made flat so as to respectively lie in parallel transverse planes which are perpendicular to the longitudinal axis 30 of the tool body 25 and are normally spaced a very close distance apart which, in the preferred embodiment of the present invention, is in the order of 0.020 to 0.030-inches.

As best seen in FIGS. 3 and 4, in the preferred embodiment of the acoustic signaler 22, the exterior of the rotating flow-obstructing member 32 is provided with a number of longitudinal grooves 36 which are cooperatively shaped to define a plurality of equally spaced, outwardly directed radial projections, as at 37, respectively having a substantially rectangular or square configuration. Although different dimensions and shapes, relative numbers, and relative proportions may be used for the grooves 29 and the projections 37 of the flowcontrolling members, it is preferable that the rotating member 32 be substantially complementally shaped with respect to the interior opening of the flowdirecting member 27. In this manner, when the flowobstructing member 32 is angularly oriented with respect to the flow-directing member 27 so as to align the projections 37 with the grooves 29, there will be a substantial momentary obstruction to the flow of the circulating mud stream through the tool 10. As pointed out in the aforementioned US. Pat. No. 3,309,656, by making the several grooves 29 and the projections 37 substantially square or rectangular, rotation of the flow-obstructing rotor 32 in relation to the flowdirecting stator 27 will repetitively obstruct the fluid passage 26 to a substantial degree and then re-open the passage as the radial projections are progressively moved into registration and then out of alignment with the grooves for producing cyclically varying sinusoidal pressure signals in the flowing drilling mud of significant amplitude at the design fundamental frequency. In other words, by virtue of the rectangular or square configurations of the grooves 29 and the radial projections 37, the effective flow area for the drilling mud passing through the tool 10 will vary continuously in a linear fashion so as to minimize the unwanted generation of acoustic signals of significant amplitudes at high-order harmonic frequencies.

Of particular significance to the present invention, it will be appreciated that instead of being fixed to its driving shaft as is the case for the siren disclosed in the aforementioned US. Pat. No. 3,309,656, the flowobstructing member 32 is slidably mounted on a sleeve 38 arranged on the shaft 33 and co-rotatively coupled to the sleeve for rotation relative thereto as by an inwardly directed spline or lug 39 on the rotating member which is slidably fitted in a helical groove 40 cooperatively arranged around the exterior of the sleeve to permit the rotor to be turned along the sleeve between its normal elevated position as depicted in FIG. 2 and at least one other relatively lower position where the rotor is more distant from the flow-directing member 27. The sleeve 3% is, in turn, co-rotatively secured to the shaft 33 by an outwardly projecting spline 41 on the shaft which is slidably fitted within a longitudinal groove 42 arranged in the interior bore of the sleeve.

To define the uppermost position of the rotor 32 in relation to the stator 27, the upper face of the sleeve 38 is counterbored, as at 43, for complementally receiving an enlarged shoulder 44 on the uppermost end of the shaft 33 and a shoulder 45 is arranged on the upper end of the sleeve to engage the upper face 35 of the rotor. Biasing means, such as a compression spring 46 having a predetermined spring force mounted in an enlarged space 47 within the sleeve 38 around the shaft 33 between the gear-reduction unit 23 and the upper end of the sleeve, are cooperatively arranged for normally urging the sleeve upwardly toward the flow-directing member so as to normally maintain the opposed faces 34 and 35 of the flow-controlling members 27 and 32 closely spaced under usual flow conditions. As depicted, it is preferred that the lower end of the spring 46 be supported by a fixed shoulder 41-8 on the shaft 33. Additional biasing means are also provided for normally maintaining the flow-obstructing member 32 at the upper end of the sleeve 38. Although a torsion spring could just as well be used, it is preferred that the additional biasing means'take the form of a compression spring 49 which is coaxially mounted on the sleeve 38 between an outwardly directed shoulder 50 on the lower end of the sleeve and the rear face of the flowobstructing member 32. In FIG. 2, the flow-obstructing member 32 is shown slightly below its usual operating position (as indicated by the dashed lines at 51) to clarify the illustration of the invention.

Accordingly, it will be appreciated that the biasing forces provided by the spring 46 and 49 will be respectively selected to maintain the flow-controlling members 27 and 32 at their desired longitudinal Spacing in relation to one another for producing acoustic signals of a desired characteristic during the normal operation of the acoustic signaler 22. However, should there be a downwardly acting force on the rotating member sufficient to overcome the upwardly directed biasing action of the spring 36, the flow-obstructing member 32 will be carried downwardly by the sleeve 38 as the sleeve is moved downwardly along the shaft 33 until such time that the downwardly acting forces on the rotating member are countered by the upwardly acting force imposed by the further compression of the spring. Similarly, should the torque required to drive the flowobstructing member 32 exceed the upwardly biasing force of the spring 49, the flow-obstructing member will be shifted downwardly along the helical path defined by the groove Ml until the spring force counters this downward travel.

In the normal course of operation of the acousticsignaling means of the present invention, the flowobstructing member 32 will be rotated at a selected constant speed for producing alternating acoustic signals having a waveform dictated by the shapes of the openings 29 and the projections 37 and at a frequency which is determined by the rotational speed of the rotating member as well as the member of the openings and projections. As various borehole conditions being measured by the measuring devices 116 and 17 change during the course of the drilling operation, the data encoder 18 will be effective for controlling the motor 21 so as to produce, for example, signals of different frequencies such as described in detail in the aforementioned U.S. Pat. No. 3,309,656. It will, of course, be appreciated that other signal-transmission modes may also be employed with the data-transmitting means 15. For example, by momentarily operating the motor 21 so as to either retard or advance the rotation of the flow-obstructing member 32, the phase relationship of the resulting output acoustic signal may be selectively varied sufficiently either in relation to previous output signals or in relation to a constant reference signal for producing other forms of distinctive acoustic signals which are also representative of the borehole conditions being monitored by the measuring devices 16 and I7. It will, of course, be appreciated that the details of such selective regulation of the motor 21 for driving the flow-obstructing member 32 to provide a given transmission mode are not necessary for an understanding of the principles of the present invention.

Accordingly, in the usual situation, the flowobstructing member 32 is steadily rotated at a speed governed by the operation of the driving motor 21 with the flow-obstructing member being at its usual operating position as shown at 51. So long as the flowobstructing member 32 is free to rotate with relation to the flow-directing member 27, the acoustic signals produced by the acoustic signaler 22 will be transmitted to the surface by way of the drilling fluid within the drill string 11 for detection and recording by the surface apparatus 24. However, as it is not at all uncommon, debris and the like which is commonly found in a borehole, such as at 13, during a typical drilling operation will be swept to the surface along with the returning drilling mud where significant portions of such debris will be picked up by the mud pumps and discharged into the drill string 11. As a result, those skilled in the art will appreciate that it is quite likely that pieces of wire, sticks, and other solid foreign materials will, from time to time, enter one or more of the grooves 29 in the flow-directing member 27 and must be carried past the rotating member 32 if rotation of the rotor is to continue. However, all too frequently, it has been found that the torque applied to the flow-obstructing member is insufficient to cut or break debris which is spanning the flow-controlling members 27 and 32 at any given moment. Thus, when this situation arises with a signaling device such as that shown in the aforementioned U.S. Pat. No. 3,309,656, the rotor described there will be easily jammed to halt the further operation of that signaling device.

In keeping with the objects of the present invention, however, the new and improved acoustic signaler 22 is cooperatively arranged for operation in a debris-laden drilling mud. Thus, with the acoustic-signaling means 20 of the present invention, should debris such as a piece of wire or a stick become lodged in two openings, as at 29 and 37, which are then aligned and thereby halt the flow-obstructing member 32 in a slightly advanced angular position where these two openings are then substantially out of registration, the resulting increased pressure differential in the flowing stream of drilling fluid will be effective for longitudinally shifting the sleeve 38 downwardly along its cooperative spline 41 on the shaft 33 to open an increased flow area for the passage of debris past the acoustic signaler 22. It will be recognized that as the sleeve 38 carries the flowobstructing member 32 away from the flow-directing member 27, the motor 21 will correspondingly turn the rotating member slightly as permitted by the length and rigidity of the piece of debris that is then lodged in the acoustic signaler 22. In some instances, separation of the flow-controlling members 27 and 32 will be sufficient for pulling the piece ofjamming debris free of the flow-directing member so that the continuing flow of the drilling mud will be effective for washing the debris out of the flow-obstructing member to restore the rotational freedom of the rotating member. Thus, once a piece of debris has been cleared from the acoustic signaler 22, the flow-obstructing member 32 will be freed and the upwardly directed biasing action of the spring 46 will be effective for returning the sleeve 38 and the rotating member to their normal positions immediately below the flow-directing member 27. Thus, the operation of acoustic-signaling means 20 will continue as before until the acoustic signaler 22 again become temporarily jammed by additional debris.

It should be recognized, however, that downward movement of the sleeve 38 caused by an increased pressure differential across the flow-controlling members 27 and 32 is contingent upon the projections 37 remaining in substantial registration with the openings 29 such as will be the case when the debris jamming the signaler 22 is a piece of wire or the like. Thus, should the piece of debris jamming the flow-controlling members 27 and 32 be a stick or something of larger diameter, the openings 36 in the rotating member could well be retained in substantial alignment with the openings 29 in the fixed member. This would, of course, result in little or no increase in pressure differential across the flow-controlling members 27 and 32 so that there would be no significant force tending to overcome the biasing action of the spring 46. Accordingly, by virtue of the helical groove 40, should a piece of larger debris become lodged in the openings 29 and 36, the continued rotational torque applied to the flow-obstructing member will be sufficient to carry the rotating member downwardly along the helical groove and thereby open up the spacing between the flow-controlling members 27 and 32 sufficiently to hopefully dislodge the debris.

It should be further noted at this point that there may well be debris when cannot be dislodge by simply shifting the flow-obstructing member 32 downwardly in relation to the flow-directing member 27. Ordinarily, this would result in a permanent jamming of the acoustic signaler 22 since the continued torque applied by the motor 21 on the piece of debris linking the flowcontrolling members 27 and 32 will simply maintain the debris in a jamming position. However, by virtue of the ability of the flow-controlling members 27 and 32 to separate, it will be appreciated that by reversing the rotation of the motor 21, the respective openings, as at 29 and 36, into which the piece of debris has been lodged can be returned into registration with one another for momentarily positioning a piece of jamming debris in a generally parallel relation to the longitudinal axis 30 so as to hopefully permit the correspondingly increased flow of drilling mud to dislodge the debris. On the other hand, should this fail, reverse rotation of the flowobstructing member 32 will pull the debris in a different direction and hopefully dislodge the debris.

In any event, once the piece of jamming debris has been cleared from the acoustic signaler 22, the flowobstructing member 32 will be quickly returned by the springs 46 and 49 to its usual position at 51 immediately below the flow-directing member 27. Once this happens, the acoustic signal will of course, be restored to continue the transmission of data or information signals to the surface. It should be noted that clearing of the debris will also flush away any accumulation of drilling mud solids on the jammed flow-controlling members 27 and 32 which will occur when the two members are halted in a misaligned position.

It will, of course, be appreciated that various circuits can be provided to selectively reverse the driving motor 21 for attaining the objects of the present invention. However, in the preferred embodiment of the datatransmitting means of the present invention, motor control circuitry 52 such as depicted in FIG. 5 is cooperatively arranged for alternately reversing the rotation of the motor 21 back and forth so long as the speed of the motor is below a desired speed. As shown there, the motor 21 is a two-phase induction motor which is selectively driven in either rotational direction by a conventional two-phase square wave power supply 53 coupled to typical driver circuits 54 connected to the two windings of the motor. To accomplish the alternate reversals of the motor 21, a typical reversing switch 55, such as a relay or suitable logic gates, is arranged to selectively reverse the leads to one of the motor windings.

To control the reversing switch 55, a typical tachometer 56 is coupled to the shaft 57 of the motor 21 and cooperatively arranged for producing an output voltage which is proportional to the rotational speed of the motor. This output voltage is preferably rectified and filtered as at 58, and supplied to one input of a comparator 59 having a reference voltage, as at 60, supplied to its other input. The output of the comparator 59 is connected to one input of a gate, such as NAND gate 61, having its output connected to the input of a counter 62. The other input of the gate 61 is connected to one of the outputs of the power supply 53 to provide a source of pulses. Any selected one of the outputs of the counter 62 is connected to the reversing switch 55. The output of the comparator 59 is also connected by way of an inverter 63 to one input of a second gate, such as a NAND gate 64, having its output connected to the reset input of the counter 62. The other input of the gate 64 is also connected to the selected output of the power supply 53.

Accordingly, in normal operation of the signaler 22, the speed of the motor 21 will be sufficient to maintain the output voltage of the tachometer 56 of such a magnitude that there will be no output signal from the comparator 59. This will correspondingly disable the gate 61 and enable the gate 64 so that there will be no output pulses supplied to the counter 62 and the counter will remain in a reset state. Once, however, the motor 21 slows such as when the acoustic signaler 22 first jams, the output voltage of the tachometer 56 will drop so as to produce an output signal from the comparator 59 which, in turn, enables the gate 61 and disables the gate 64. Once the gate 61 is enabled, the pulses from the power supply 53 will be supplied to the counter 62. Thus, each time the number of pulses supplied to the counter 62 reach a number capable of producing an output signal at the connected output of the counter, the reversing switch will be energized or activated to reverse the rotation of the motor 21. The pulses will, of course, continue to be supplied to the counter 62 so long as the speed of the motor 21 'is below its normal range. This will, therefore, accomplish a second reversal of the motor 21 once there is a subsequent output from the counter 62 which again energizes or activates the reversing switch 55. Thus, reversal of the motor 21 will be repeated at frequent intervals such as every few seconds or so as long as the tachometer 56 indicates that the speed of the motor is below its normal operating speed and accordingly maintains the gate 61 in an enabled state. Once the speed of the motor 21 again increases, the gate 61 will again be disabled and the gate 64 will again be enabled to reset the counter 62 so that the reversing switch 55 will again be positioned to return the motor 21 to its original direction of rotation.

Accordingly, it will be appreciated that the present invention has provided new and improved well bore apparatus for transmitting information or data signals representative of one or more downhole conditions to the surface during the course of a drilling operation. By arranging the acoustic signaling means of the present invention to include a rotating flow-obstructing member which is cyclically rotated in the proximity of the flowdirecting member as the drilling fluid is circulated past these members, an acoustic signal of a frequency re lated to the design of these members and the rotational speed of the rotating member is produced. To prevent debris and the like which is typically carried in a circulating stream of drilling mud from jamming the signaling means, the rotating member is cooperatively arranged for sliding movement in relation to its supporting shaft to permit the flow-controlling members to be separated either in response to increased torque or increased pressure differential caused by jamming thereby opening the normal close spacing between the two members a sufficient amount to allow the drilling fluid to wash the debris free of the acoustic-signaling means. Biasing means are cooperatively arranged for restoring the rotating member to its normal position once the piece of jamming debris has been cleared from the acoustic-signaling means.

While only a particular embodiment of the present invention has been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects; and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. Apparatus adapted for transmitting data signals from a well bore to the surface and comprising:

a body adapted for connection in a pipe string and having a fluid passage arranged to carry debrisbearing fluids between the surface and well bore;

a first signal-producing member cooperatively arranged in said fluid passage for directing at least a portion of a fluid flowing therethrough along at least one selected flow path;

first means including a second signal-producing member cooperatively arranged in said flow passage adjacent to said first member for rotation at a selected speed in a plane transverse to said flow path for repetitively obstructing said flow path at periodic intervals to cyclically produce acoustic data signals in a fluid flowing through said fluid passage; and

second means operable upon at least slowing of said second member below said selected speed in response to either an increased pressure differential across said signal-producing members or an increase in driving torque on said second member for momentarily separating said signal-producing members to allow fluid-borne solids flowing through said fluid passage to pass downstream of said signal-producing members.

2. The apparatus of claim 1 wherein said first means include a rotatable motor, and means cooperatively coupling said second member to said motor for rotation thereby as well as for movement relative thereto between an operating position adjacent to said first member and a debris-clearing position more distant therefrom; and said second means include biasing means oooperatively arranged for normally urging said second member toward its said operating position and yieldable in response to an increased driving torque for said second member characteristic of the slowing of said second member for allowing said second member to move at least momentarily toward its said debrisclearing position.

3. The apparatus of claim 1 wherein said motor is a selectively reversible electric motor; and further including circuit means responsive to the slowing of said second member for selectively reversing the rotational direction of said motor.

4. The apparatus of claim ll wherein said first means include a rotatable motor, a rotatable shaft drivingly coupled to said motor, and means cooperatively coupling said second member to said shaft for rotation thereby as well as for movement therealong between an operating position adjacent to said first member and a debris-clearing position more distant therefrom; and said second means include first biasing means normally biasing said second member toward its said operating position and yieldable in response to an increased pressure differential characteristic of the slowing of the rotational speed of said second member for allowing said second member to move at least momentarily toward its said debris-clearing position, and second biasing means normally biasing said second member toward its said operating position and yieldable in response to an increased driving torque for said second member characteristic of the slowing of the rotational speed of said second member for allowing said second member to move at least momentarily toward its said debrisclearing position.

5. The apparatus of claim 4 wherein said motor is a selectively reversible electric motor; and further including circuit means responsive to the slowing of said second member for selectively reversing the rotational direction of said motor.

6. The apparatus of claim 5 wherein said circuit means are selectively operable for alternately reversing the rotational direction of said motor back and forth so long as said second member is slowed below said selected speed.

7. Apparatus adapted for transmitting data to the surface during the drilling of a borehole and comprising:

a body adapted for connection in a tubular drill string and having a fluid passage arranged to conduct drilling fluids between the surface and a borehole drilling device dependently coupled therebelow;

a flow director cooperatively arranged in said fluid passage and including at least one opening for directing drilling fluids flowing through said fluid passage along a selected axis;

a signal-producing member coaxially arranged for rotation in said fluid passage and including a plurality of alternately disposed openings and obstructions angularly spaced from one another and respectively adapted to successively cut across said axis upon rotation of said signal-producing member for cyclically producing acoustic data signals in a drilling fluid flowing through said fluid passage;

motor means adapted for rotating said signalproducing member at at least one selected rotational speed; and

coupling means selectively coupling said motor means to said signal-producing member and opera ble in response to at least slowing of said signallill producing member by fluid-borne debris for momentarily moving said signal-producing member away from said flow director either when there is an increase in pressure differential across said signal-producing member or when there is an increase in driving torque on said signal-producing member to allow such debris to be carried downstream of said flow director by drilling fluids flowing through said fluid passage.

8. The apparatus of claim 7 wherein said flow director is fixed within said fluid passage.

9. The apparatus of claim 7 further including control means coupled to said motor means and responsive to slowing of said signal-producing member below said selected speed for also rotatively moving said signalproducing member back and forth in relation to said flow director so long as said signal-producing member is slowed below said selected speed.

10. The apparatus of claim 9 wherein said motor means include a reversible electric motor; and said control means include means operable upon slowing of said motor for producing an electric signal, and means responsive to said electrical signal for repetitively reversing said motor.

Ill. The apparatus of claim 7 wherein said coupling means include a rotatable shaft member cooperatively coupled to said motor means for rotation thereby, and a coupling arranged between said shaft member and said signal-producing member, first guide means cooperatively arranged between said coupling and one of said members and including a first guide and means defining a first guide path extending between longitudinally spaced first positions, second guide means cooperatively arranged between said coupling and the other of said members and including a second guide and means defining a second guide path extending between longitudinally spaced second positions, first biasing means between said coupling and said one member normally urging said one member toward said flow director and yieldable in response to an increase in pressure differential across said signal-producing member for allowing said one member to move at least momentarily along said first guide path away from said flow director, and second biasing means between said coupling and said other member normally urging said other member toward said flow director and yieldable in response to an increase in rotative torque to drive said signal-producing member for allowing said other member to move at least momentarily along said second guide path away from said flow director.

12. The apparatus of claim 11 wherein one of said guide paths is helically configured.

13. The apparatus of claim lll wherein said one member is said shaft member and said other member is said signal-producing member.

14. The apparatus of claim 13 wherein said coupling is a tubular member coaxially disposed around said shaft member and within said signal-producing member, and said second guide path is a generally helical passage defined around said tubular coupling member so that upon yielding of said second biasing means said signal-producing member will move in a generally helical path along said tubular coupling member away from said flow director.

15. The apparatus of claim 14 wherein said first guide path is a generally longitudinal passage so that upon yielding of said first biasing means said tubular coupling member and said signal-producing member will move in a generally longitudinal path along said shaft member away from said flow director.

16. Apparatus adapted for measuring at least one downhole condition while drilling a borehole and comprising:

a body tandemly coupled in a tubular drill string having a borehole-drilling device dependently coupled thereto and defining a fluid passage for circulating drilling fluids between the surface and said borehole-drilling device;

data-signaling means on said body and adapted for producing electrical signals representative of at least one downhole condition;

acoustic-signaling means on said body and including an electric motor coupled to said data-signaling means for selective rotation in response to said electrical signals, a flow-directing member in said fluid passage and having a plurality of spaced openings cooperatively arranged for directing drilling fluids in selected fluid paths along said fluid passage, and a rotatable flow-obstructing member in said fluid passage and having a plurality of alternately distributed angularly spaced openings and obstructions cooperatively arranged to successively cross said fluid paths upon rotation of said flow-obstructing member for producing cyclic acoustic signals representative of said electrical signals in drilling fluids flowing through said fluid passage;

first means cooperatively coupling said flowobstructing member to said motor for rotation thereby at at least one selected rotational speed and responsive to an increase in the torque required to maintain said flow-obstructing member at said selected speed for moving said flowobstructing member away from said flow-directing member upon slowing of said flow-obstructing member to clear fluid-borne debris from between said members; and

second means responsive to an increased pressure differential across said flow-obstructing member for moving one of said members away from the other of said members upon slowing of said flowobstructing member to clear such fluid-borne debris from between said members.

17. The apparatus of claim 16 further including con trol means coupled to said motor and responsive to slowing of said flow-obstructing member below said selected speed for alternately rotating said motor back and forth in opposite rotative directions so long as said flow-obstructing member is slowed below said selected speed.

18. The apparatus of claim 16 wherein said flowobstructing member is downstream of said flowdirecting member.

19. The apparatus of claim 16 wherein said one member is said flow-obstructing member; said first means include a rotatable shaft coupled to said motor, and means co-rotatively coupling said flow-obstructing member to said shaft; and said second means include means operable upon increased pressure differentials across said members for shifting said flow-obstructing member along said shaft away'from said flow-directing member and operable upon the subsequent decrease in such increased pressure differentials for shifting said flow-obstructing member along said shaft toward said flow-directing member.

20. The apparatus of claim 19 further including con trol means coupled to said motor and responsive to slowing of said flow'obstructing member below said selected speed for alternately rotating said motor back and forth in opposite rotative directions so long as said flow-obstructing member is slowed below said selected speed.

21. The apparatus of claim 16 wherein said flowdirecting member is fixed in relation to said body and is coaxially arranged in said fluid passage upstream of said flow-obstructing member.

22. Apparatus adapted for measuring at least one downhole condition while drilling a borehole and comprising:

a body tandemly coupled in a tubular drill string having a borehole-drilling device dependently coupled thereo and defining a fluid passage for circulating drilling fluids between the surface and said borehole-drilling device;

data-signaling means on said body and adapted for producing electrical signals representative of at least one downhole condition;

acoustic-signaling means on said body and including an electric motor coupled to said data-signaling means for selective rotation in response to said electrical signals, a flow director coaxially arranged in said fluid passage and having a plurality of spaced openings cooperatively arranged for directing drilling fluids in selected fluid paths along said fluid passage, an annular signal-producing member coaxially arranged in said fluid passage and having a plurality of alternately distributed angularly spaced openings and obstructions cooperatively arranged to successively cross said fluid paths upon rotation of said signal-producing member for producing cyclic acoustic signals representative of said electrical signals in drilling fluids flowing through said fluid passage; and

means adapted for selectively driving said signalproducing member including a rotatable shaft member cooperatively coupled to said motor for rotation thereby, a coupling disposed between said shaft member and said signal-producing member, first guide means cooperatively arranged between said coupling and one of said members and including a first guide and means defining a first guide path extending between longitudinally spaced first positions, second guide means cooperatively arranged between said coupling and the other of said members and including a second guide and means defining a second guide path extending between longitudinally spaced second positions, first biasing means between said coupling and said one member normally urging one member toward said flow director and yieldable in response to an increase in pressure differential across said signal-producing member for allowing said one member to move at least momentarily along said first guide path away from said flow director, and second biasing means between said coupling and said other member normally urging said other member toward said flow director and yieldable in response to an increase in rotative torqueto drivesaid signal-producing member for allowingsaid other member to move at least momentarily along said second guide path away from said flow director.

23. The apparatus of claim 22 wherein one of said guide paths is helically configured.

24. The apparatus of claim 22 wherein said one member is said shaft member and said other member is said signal-producing member.

25. The apparatus of claim 24 wherein said coupling is a tubular member coaxially disposed around said shaft member and within said signal-producing member, and said second guide path is a generally helical passage defined around said tubular coupling member so that upon yielding of said second biasing means said signal-producing member will move in a generally helical path along said tubular coupling member away from said flow director. 

1. Apparatus adapted for transmitting data signals from a well bore to the surface and comprising: a body adapted for connection in a pipe string and having a fluid passage arranged to carry debris-bearing fluids between the surface and well bore; a first signal-producing member cooperatively arranged in said fluid passage for directing at least a portion of a fluid flowing therethrough along at least one selected flow path; first means including a second signal-producing member cooperatively arranged in said flow passage adjacent to said first member for rotation at a selected speed in a plane transverse to said flow path for repetitively obstructing said flow path at periodic intervals to cyclically produce acoustic data signals in a fluid flowing through said fluid passage; and second means operable upon at least slowing of said second member below said selected speed in response to either an increased pressure differential across said signal-producing members or an increase in driving torque on said second member for momentarily separating said signal-producing members to allow fluid-borne solids flowing through said fluid passage to pass downstream of said signal-producing members.
 2. The apparatus of claim 1 wherein said first means include a rotatable motor, and means cooperatively coupling said second member to said motor for rotation thereby as well as for movement relative thereto between an operating position adjacent to said first member and a debris-clearing position more distant therefrom; and said second means include biasing means cooperatively arranged for normally urging said second member toward its said operating position and yieldable in response to an increased driving torque for said second member characteristic of the slowing of said second member for allowing said second member to move at least momentarily toward its said debris-clearing position.
 3. The apparatus of claim 1 wherein said motor is a selectively reversible electric motor; and further including circuit means responsive to the slowing of said second member for selectively reversing the rotational direction of said motor.
 4. The apparatus of claim 1 wherein said first means include a rotatable motor, a rotatable shaft drivingly coupled to said motor, and means cooperatively coupling said second member to said shaft for rotation thereby as well as for movement therealong between an operating position adjacent to said first member and a debris-clearing position more distant therefrom; and said second means include first biasing means normally biasing said second member toward its said operating position and yieldable in response to an increased pressure differential characteristic of the slowing of the rotational speed of said second member for allowing said second member to move at least momentarily toward its said debris-clearing position, and second biasing means normally biasing said second member toward its said operating position and yieldable in response to an increased driving torque for said second member characteristic of the slowing of the rotational speed of said second member for allowing said second member to move at least momentarily toward its said debris-clearing position.
 5. The apparatus of claim 4 wherein said motor is a selectively reversible electric motor; and further including circuit means responsive to the slowing of said second member for selectively reversing the rotational direction of said motor.
 6. The apparatus of claim 5 wherein said circuit means are selectively operable for alternately reversing the rotational direction of said motor back and forth so long as said second member is slowed below said selected speed.
 7. Apparatus adapted for transmitting data to the surface during thE drilling of a borehole and comprising: a body adapted for connection in a tubular drill string and having a fluid passage arranged to conduct drilling fluids between the surface and a borehole-drilling device dependently coupled therebelow; a flow director cooperatively arranged in said fluid passage and including at least one opening for directing drilling fluids flowing through said fluid passage along a selected axis; a signal-producing member coaxially arranged for rotation in said fluid passage and including a plurality of alternately disposed openings and obstructions angularly spaced from one another and respectively adapted to successively cut across said axis upon rotation of said signal-producing member for cyclically producing acoustic data signals in a drilling fluid flowing through said fluid passage; motor means adapted for rotating said signal-producing member at at least one selected rotational speed; and coupling means selectively coupling said motor means to said signal-producing member and operable in response to at least slowing of said signal-producing member by fluid-borne debris for momentarily moving said signal-producing member away from said flow director either when there is an increase in pressure differential across said signal-producing member or when there is an increase in driving torque on said signal-producing member to allow such debris to be carried downstream of said flow director by drilling fluids flowing through said fluid passage.
 8. The apparatus of claim 7 wherein said flow director is fixed within said fluid passage.
 9. The apparatus of claim 7 further including control means coupled to said motor means and responsive to slowing of said signal-producing member below said selected speed for also rotatively moving said signal-producing member back and forth in relation to said flow director so long as said signal-producing member is slowed below said selected speed.
 10. The apparatus of claim 9 wherein said motor means include a reversible electric motor; and said control means include means operable upon slowing of said motor for producing an electric signal, and means responsive to said electrical signal for repetitively reversing said motor.
 11. The apparatus of claim 7 wherein said coupling means include a rotatable shaft member cooperatively coupled to said motor means for rotation thereby, and a coupling arranged between said shaft member and said signal-producing member, first guide means cooperatively arranged between said coupling and one of said members and including a first guide and means defining a first guide path extending between longitudinally spaced first positions, second guide means cooperatively arranged between said coupling and the other of said members and including a second guide and means defining a second guide path extending between longitudinally spaced second positions, first biasing means between said coupling and said one member normally urging said one member toward said flow director and yieldable in response to an increase in pressure differential across said signal-producing member for allowing said one member to move at least momentarily along said first guide path away from said flow director, and second biasing means between said coupling and said other member normally urging said other member toward said flow director and yieldable in response to an increase in rotative torque to drive said signal-producing member for allowing said other member to move at least momentarily along said second guide path away from said flow director.
 12. The apparatus of claim 11 wherein one of said guide paths is helically configured.
 13. The apparatus of claim 11 wherein said one member is said shaft member and said other member is said signal-producing member.
 14. The apparatus of claim 13 wherein said coupling is a tubular member coaxially disposed around said shaft member and within said signal-producing member, and said second guide path is a generally helical Passage defined around said tubular coupling member so that upon yielding of said second biasing means said signal-producing member will move in a generally helical path along said tubular coupling member away from said flow director.
 15. The apparatus of claim 14 wherein said first guide path is a generally longitudinal passage so that upon yielding of said first biasing means said tubular coupling member and said signal-producing member will move in a generally longitudinal path along said shaft member away from said flow director.
 16. Apparatus adapted for measuring at least one downhole condition while drilling a borehole and comprising: a body tandemly coupled in a tubular drill string having a borehole-drilling device dependently coupled thereto and defining a fluid passage for circulating drilling fluids between the surface and said borehole-drilling device; data-signaling means on said body and adapted for producing electrical signals representative of at least one downhole condition; acoustic-signaling means on said body and including an electric motor coupled to said data-signaling means for selective rotation in response to said electrical signals, a flow-directing member in said fluid passage and having a plurality of spaced openings cooperatively arranged for directing drilling fluids in selected fluid paths along said fluid passage, and a rotatable flow-obstructing member in said fluid passage and having a plurality of alternately distributed angularly spaced openings and obstructions cooperatively arranged to successively cross said fluid paths upon rotation of said flow-obstructing member for producing cyclic acoustic signals representative of said electrical signals in drilling fluids flowing through said fluid passage; first means cooperatively coupling said flow-obstructing member to said motor for rotation thereby at at least one selected rotational speed and responsive to an increase in the torque required to maintain said flow-obstructing member at said selected speed for moving said flow-obstructing member away from said flow-directing member upon slowing of said flow-obstructing member to clear fluid-borne debris from between said members; and second means responsive to an increased pressure differential across said flow-obstructing member for moving one of said members away from the other of said members upon slowing of said flow-obstructing member to clear such fluid-borne debris from between said members.
 17. The apparatus of claim 16 further including control means coupled to said motor and responsive to slowing of said flow-obstructing member below said selected speed for alternately rotating said motor back and forth in opposite rotative directions so long as said flow-obstructing member is slowed below said selected speed.
 18. The apparatus of claim 16 wherein said flow-obstructing member is downstream of said flow-directing member.
 19. The apparatus of claim 16 wherein said one member is said flow-obstructing member; said first means include a rotatable shaft coupled to said motor, and means co-rotatively coupling said flow-obstructing member to said shaft; and said second means include means operable upon increased pressure differentials across said members for shifting said flow-obstructing member along said shaft away from said flow-directing member and operable upon the subsequent decrease in such increased pressure differentials for shifting said flow-obstructing member along said shaft toward said flow-directing member.
 20. The apparatus of claim 19 further including control means coupled to said motor and responsive to slowing of said flow-obstructing member below said selected speed for alternately rotating said motor back and forth in opposite rotative directions so long as said flow-obstructing member is slowed below said selected speed.
 21. The apparatus of claim 16 wherein said flow-directing member is fixed in relation to said body and is coaxially arranged in said fluid passage upstreAm of said flow-obstructing member.
 22. Apparatus adapted for measuring at least one downhole condition while drilling a borehole and comprising: a body tandemly coupled in a tubular drill string having a borehole-drilling device dependently coupled thereo and defining a fluid passage for circulating drilling fluids between the surface and said borehole-drilling device; data-signaling means on said body and adapted for producing electrical signals representative of at least one downhole condition; acoustic-signaling means on said body and including an electric motor coupled to said data-signaling means for selective rotation in response to said electrical signals, a flow director coaxially arranged in said fluid passage and having a plurality of spaced openings cooperatively arranged for directing drilling fluids in selected fluid paths along said fluid passage, an annular signal-producing member coaxially arranged in said fluid passage and having a plurality of alternately distributed angularly spaced openings and obstructions cooperatively arranged to successively cross said fluid paths upon rotation of said signal-producing member for producing cyclic acoustic signals representative of said electrical signals in drilling fluids flowing through said fluid passage; and means adapted for selectively driving said signal-producing member including a rotatable shaft member cooperatively coupled to said motor for rotation thereby, a coupling disposed between said shaft member and said signal-producing member, first guide means cooperatively arranged between said coupling and one of said members and including a first guide and means defining a first guide path extending between longitudinally spaced first positions, second guide means cooperatively arranged between said coupling and the other of said members and including a second guide and means defining a second guide path extending between longitudinally spaced second positions, first biasing means between said coupling and said one member normally urging one member toward said flow director and yieldable in response to an increase in pressure differential across said signal-producing member for allowing said one member to move at least momentarily along said first guide path away from said flow director, and second biasing means between said coupling and said other member normally urging said other member toward said flow director and yieldable in response to an increase in rotative torque to drive said signal-producing member for allowing said other member to move at least momentarily along said second guide path away from said flow director.
 23. The apparatus of claim 22 wherein one of said guide paths is helically configured.
 24. The apparatus of claim 22 wherein said one member is said shaft member and said other member is said signal-producing member.
 25. The apparatus of claim 24 wherein said coupling is a tubular member coaxially disposed around said shaft member and within said signal-producing member, and said second guide path is a generally helical passage defined around said tubular coupling member so that upon yielding of said second biasing means said signal-producing member will move in a generally helical path along said tubular coupling member away from said flow director. 